POJ.2976 Dropping tests

1.Problem
http://poj.org/problem?id=2976

2.Idea
Binary Search

3.Source

 int N, K;  
 int a[1003];  
 int b[1003];  
 double y[1003];  
 bool C(double x)  
 {  
      for (int i = 0; i < N; i++) {  
           y[i] = (double)a[i] - x * (double)b[i];  
      }  
      sort(y, y + N);  
      double sum = 0.0;  
      for (int i = K; i < N; i++) sum += y[i];  
      return sum >= 0;  
 }  
 void solve()  
 {  
      double l = 0.0, r = 1.0;  
      for (int i = 0; i < 100; i++) {  
           double m = (l + r) * 0.5;  
           if (C(m)) {  
                l = m;  
           }  
           else {  
                r = m;  
           }  
      }  
      cout << (int)(100.0 * l + 0.5) << endl;  
 }  
 int main()  
 {  
      while (scanf("%d%d", &N, &K) > 0) {  
           if (N + K == 0) break;  
           for (int i = 0; i < N; i++) cin >> a[i];  
           for (int i = 0; i < N; i++) cin >> b[i];  
           solve();  
      }  
      return 0;  
 }